Up to 450 workers at a Hyundai Motor facility under construction in Georgia have been detained in a major raid by U.S. authorities that has led to a pause in the project to build a car battery factory.

The raid on Thursday led to a pause in the project, which is part of what would be the biggest investments in the state, and illustrates the increasing crackdown by the Trump administration on immigrants and its impact on businesses.

An agent at the U.S. Department of Homeland Security (DHS) said multiple U.S. agencies "conducted a judicially authorised enforcement operation, as we are actively conducting an investigation into unlawful employment practices."

"Arrests are being made," Steven Schrank, special agent in charge of Homeland Security Investigations for Georgia, said in a news briefing aired on U.S. television.

A Korean news report said about 30 South Korean nationals had been detained.

The battery production facility, a joint venture between South Korean battery maker LG Energy Solution (LGES) and Hyundai Motor, was due to start operations at the end of this year, according to LGES. A spokesperson at the Hyundai-GA battery company said in a statement that it was "cooperating fully with the appropriate authorities regarding activity at our construction site" and that it had paused construction work to assist.

Under President Donald Trump, the Immigration and Customs Enforcement (ICE) agency, which is part of the Department of Homeland Security, has become the driving force of the Republican leader's sweeping crackdown on migrants.